Note: Descriptions are shown in the official language in which they were submitted.
020171-0004
PROCESS FOR TREATING A WOOD SUBSTRATE AND WATER-BASED
WOOD TREATMENT SOLUTION AND KIT ASSOCIATED THEREWITH
RELATED APPLICATION
[0001] This application claims priority to United States provisional
application No.
62/984,333 filed on March 3, 2020.
TECHNICAL FIELD
[0002] The present disclosure relates to processes, water-based wood treatment
solutions and kits for treating wood substrates. More particularly, the
present
disclosure relates to processes, water-based wood treatment solutions and kits
for
rapidly coloring wood substrates to mimic the appearance of aged wood
substrate.
BACKGROUND
[0003] Oxidation is a natural process that wood undergoes as it ages. Over
time,
the exposure to oxygen and UV rays from the sun causes a wooden board to
either
lighten or darken, depending on the wood species. Repeated changes in moisture
and exposure to elements like wind and rain can also accelerate the aging of
wood.
[0004] Although the wood surface is damaged in the process, an aged barn door
or
weathered beam can be appealing. Indeed, obtaining a vintage look is something
which many people desire, as aged wood is a popular material used for both
interior
and exterior applications. However, obtaining a wood substrate with an already
rustic
look can be long, difficult and expensive.
[0005] It is already known in the art to accelerate the natural oxidation of a
wood
substrate. For example, it is already known that mixing steel wool into
vinegar
creates ferrous and ferric acetate in solution, which, once applied to the
surface of a
wood substrate, can color it to provide it with an aging effect.
[0006] Even though the combination of steel wool and vinegar as an artificial
ageing
solution is already known in the art, this approach presents several
drawbacks. For
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example, reaching complete dissolution of the steel wool in the vinegar can
take
several days. Moreover, the nature and concentrations of the reactive species
(in
the steel wool for example) are unknown, which can lead to different end
results
using different quantities and brands of steel wool and vinegar. In addition,
the
solution obtained has an unpleasant odor and precipitates, which could bring
unwanted deposits once applied to the wood substrate.
[0007] There is therefore a need for improved processes, water-based wood
treatment solutions and kits for rapidly coloring wood substrates so as to
mimic the
appearance of aged wood substrate, and which, by virtue of their steps or
components, would be able to overcome or at least minimize some of the above-
discussed concerns.
SUMMARY
[0008] It is an object of the present disclosure to provide processes, water-
based
wood treatment solutions and kits for treating wood substrates that overcome
or
mitigate one or more disadvantages of known processes, wood treatment
solutions
and kits for treating wood substrates, or at least provide useful
alternatives.
[0009] In accordance with an embodiment, there is provided a kit for treating
a wood
substrate, the kit comprising: a pouch comprising a water-soluble metal (II)
salt in
solid form; a pouch comprising a water-soluble acetate salt in solid form; a
pouch
comprising a water-soluble tannin-rich material in solid form; and a user
guide
providing instructions for dissolving a dose of the water-soluble metal (II)
salt and a
dose of the water-soluble acetate salt in an amount of an aqueous solvent to
thereby
obtain a water-based wood treatment solution having a concentration of water-
soluble metal (II) salt and water-soluble acetate salt sufficient to allow the
water-
based wood treatment solution to color the wood substrate, and instructions:
for
dissolving a dose of the water-soluble tannin-rich material in the aqueous
solvent
along with the water-soluble metal (II) salt and the water-soluble acetate
salt; or for
dissolving a dose of the water-soluble tannin-rich material in another aqueous
solvent to thereby obtain a water-based tannin-rich treatment solution having
a
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concentration of water-soluble tannin-rich material sufficient to allow the
water-
based tannin-rich treatment solution to at least partially saturate the wood
substrate.
[0010] In one implementation, the water-soluble metal (II) salt and the water-
soluble
acetate salt are provided in form of solid powders.
[0011] In one implementation, the water-soluble tannin-rich material are
provided in
form of solid powders.
[0012] In one implementation, at least the pouch comprising the water-soluble
metal
(II) salt and the pouch comprising the water-soluble acetate salt are hermetic
pouches.
[0013] In one implementation, the water-soluble metal (II) salt comprises a
water-
soluble iron (II) salt. The water-soluble iron (II) salt can comprise an iron
(II) chloride,
an iron (II) perchlorate, an iron (II) sulfate, or any combination thereof.
More
particularly, the water-soluble iron (II) salt can comprise an iron (II)
sulfate
monohydrate, an iron (II) sulfate heptahydrate, an iron (II)
ethylenediammonium
sulfate, or any combination thereof. For example, the water-soluble iron (II)
salt can
be iron (II) sulfate heptahydrate.
[0014] In one implementation, the concentration of the water-soluble metal
(II) salt
in the water-based wood treatment solution is between about 1 g/L and about 10
g/L, between about 1.5 g/L and about 7 g/L, between about 2 g/L and about 5
g/L or
between about 2 g/L and about 3 g/L.
[0015] In one implementation, the water-soluble acetate salt comprises a
sodium
acetate, a calcium diacetate x - hydrate, or any combination thereof. For
example,
the sodium acetate can comprise sodium acetate trihydrate.
[0016] In one implementation, the concentration of the water-soluble acetate
salt in
the water-based wood treatment solution is between about 1 g/L and about 10
g/L,
between about 2 g/L and about 5 g/L or between about 2 g/L and about 3 g/L.
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[0017] In one implementation, the aqueous solvent is water.
[0018] In one implementation, the pH of the water-based wood treatment
solution is
adjusted to between about 4 and about 7, between about 5 and about 6 or
between
about 4 and about 5.
[0019] In one implementation, the water-soluble tannin-rich material has a
tannin
content greater than 40%, greater than 50%, greater than 60%, greater than
70%,
greater than 80%, or greater than 90%.
[0020] In one implementation, the water-soluble tannin-rich material comprises
a
logwood tree extract, a mimosa tree extract, an oak gall extract, a tea
extract, a wine
extract, a coffee extract, or any combination thereof.
[0021] In one implementation, the concentration of the water-soluble tannin-
rich
material in the water-based wood treatment solution is between about 2 g/L and
about 100 g/L, or between about 2 g/L and about 50 g/L.
[0022] In one implementation, the concentration of the water-soluble tannin-
rich
material in the water-based tannin-rich treatment solution is between about 2
g/L
and about 25 g/L or between about 2 g/L and about 5 g/L.
[0023] In one implementation, the kit further comprises a pouch comprising a
water-
soluble acid in solid form; wherein the user guide further provides
instructions for
dissolving a dose of the water-soluble acid in the aqueous solvent along with
the
water-soluble metal (II) salt and the water-soluble acetate salt so as to
adjust the pH
of the water-based wood treatment solution.
[0024] In one implementation, the molar ratio of the water-soluble acid, the
water-
soluble metal (II) salt and the water-soluble acetate salt in the water-based
wood
treatment solution is between about 1:3:6 and about 1:3:30.
[0025] In one implementation, the water-soluble acid is provided in form of
solid
powders. The water-soluble acid can comprise a sulfuric acid, an acetic acid,
a citric
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acid, or any combination thereof. For example, the citric acid can comprise an
anhydrous citric acid.
[0026] In accordance with another embodiment, there is provided a process for
treating a wood substrate comprising the steps of: providing a first aqueous
solvent;
dissolving a water-soluble metal (II) salt in solid form and a water-soluble
acetate
salt in solid form in the first aqueous solvent to obtain a water-based wood
treatment
solution, the water-soluble metal (II) salt and the water-soluble acetate salt
being
added in the first aqueous solvent in sufficient concentration to allow the
water-based
wood treatment solution to color the wood substrate; and one of: dissolving a
water-
soluble tannin-rich material in solid form in the first aqueous solvent
together with
the water-soluble metal (II) salt and the water-soluble acetate salt; and
contacting
the wood substrate with the water-based wood treatment solution for a contact
time
sufficient to color the wood substrate; and dissolving a water-soluble tannin-
rich
material in solid form in a second aqueous solvent to obtain a water-based
tannin-
rich treatment solution, the water-soluble tannin-rich material being added in
the
second aqueous solvent in sufficient concentration to allow the water-based
tannin-
rich treatment solution to at least partially saturate the wood substrate;
contacting
the wood substrate with the water-based tannin-rich treatment solution to at
least
partially saturate the wood substrate; and contacting the wood substrate with
the
water-based wood treatment solution for a contact time sufficient to color the
wood
substrate.
[0027] In one implementation, the wood substrate is contacted with the water-
based
tannin-rich treatment solution prior to or after the wood substrate has been
contacted
with the water-based wood treatment solution.
[0028] In one implementation, the wood substrate is first contacted with the
water-
based tannin-rich treatment solution to obtain a pretreated wood substrate,
and then
the pretreated wood substrate is contacted with the water-based wood treatment
solution.
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[0029] In one implementation, the process further comprises: preventing direct
contact between the water-soluble metal (II) salt and the water-soluble
acetate salt
prior to dissolving the water-soluble metal (II) salt and the water-soluble
acetate salt
in the first aqueous solvent.
[0030] In one implementation, the water-soluble metal (II) salt and the water-
soluble
acetate salt are in the form of solid powders.
[0031] In one implementation, the water-soluble tannin rich material is in the
form of
solid powders.
[0032] In one implementation, the water-soluble metal (II) salt comprises a
water-
soluble iron (II) salt.
[0033] In one implementation, the water-soluble iron (II) salt comprises an
iron (II)
chloride, an iron (II) perchlorate, an iron (II) sulfate, or any combination
thereof. More
particularly, the water-soluble iron (II) salt can comprise an iron (II)
sulfate
monohydrate, an iron (II) sulfate heptahydrate, an iron (II)
ethylenediammonium
sulfate, or any combination thereof. For example, the water-soluble iron (II)
salt can
be iron (II) sulfate heptahydrate.
[0034] In one implementation, the concentration of the water-soluble metal
(II) salt
in the water-based wood treatment solution is between about 1 g/L and about 10
g/L, between about 1.5 g/L and about 7 g/L, between about 2 g/L and about 5
g/L or
between about 2 g/L and about 3 g/L.
[0035] In one implementation, the water-soluble acetate salt comprises a
sodium
acetate, a calcium diacetate x - hydrate, or any combination thereof. For
example,
the sodium acetate can comprise sodium acetate trihydrate.
[0036] In one implementation, the concentration of the water-soluble acetate
salt in
the water-based wood treatment solution is between about 1 g/L and about 10
g/L,
between about 2 g/L and about 5 g/L or between about 2 g/L and about 3 g/L.
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[0037] In one implementation, the first aqueous solvent is water.
[0038] In one implementation, the second aqueous solvent is also water.
[0039] In one implementation, the water-soluble tannin-rich material has a
tannin
content greater than 40%, greater than 50%, greater than 60%, greater than
70%,
greater than 80%, or greater than 90%.
[0040] In one implementation, the water-soluble tannin-rich material comprises
a
logwood tree extract, a mimosa tree extract, an oak gall extract, a tea
extract, a wine
extract, a coffee extract, or any combination thereof.
[0041] In one implementation, the concentration of the water-soluble tannin-
rich
material in the water-based wood treatment solution is between about 2 g/L and
about 100 g/L, or between about 2 g/L and about 50 g/L.
[0042] In one implementation, the concentration of the water-soluble tannin-
rich
material in the water-based tannin-rich treatment solution is between about 2
g/L
and about 25 g/L or between about 2 g/L and about 5 g/L.
[0043] In one implementation, the process further comprises the step of:
dissolving
a water-soluble acid is solid form in the first aqueous solvent before
contacting the
wood substrate with the water-based wood treatment solution.
[0044] In one implementation, the molar ratio of the water-soluble acid, the
water-
soluble metal (II) salt, and the water-soluble acetate salt in the water-based
wood
treatment solution is between about 1:3:6 and about 1:3:30.
[0045] In one implementation, the water-soluble acid is in the form of solid
powders.
[0046] In one implementation, the water-soluble acid is added in a quantity
such that
the pH of the water-based wood treatment solution is between about 4 and about
7,
between about 5 and about 6 or between about 4 and about 5.
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[0047] In one implementation, the water-soluble acid comprises a sulfuric
acid, an
acetic acid, a citric acid, or any combination thereof. For example, the
citric acid can
comprise an anhydrous citric acid.
[0048] In accordance with a further embodiment, there is provided a kit for
treating
a wood substrate, the kit comprising: a pouch comprising a water-soluble
tannin-rich
material in solid form; and a user guide providing instructions for dissolving
a dose
of the water-soluble tannin-rich material in an aqueous solvent to thereby
obtain a
water-based tannin-rich treatment solution having a concentration of water-
soluble
tannin-rich material sufficient to allow the water-based tannin-rich treatment
solution
to at least partially saturate the wood substrate.
[0049] In one implementation, the water-soluble tannin-rich material is
provided in
form of solid powders.
[0050] In one implementation, the water-soluble tannin-rich material comprises
a
logwood tree extract, a mimosa tree extract, an oak gall extract, a tea
extract, a wine
extract, a coffee extract, or any combination thereof.
[0051] In one implementation, the concentration of the water-soluble tannin-
rich
material in the water-based tannin-rich treatment solution is between about 2
g/L
and about 25 g/L or between about 2 g/L and about 5 g/L.
DETAILED DESCRIPTION
[0052] The present description relates to a process for treating a wood
substrate in
order to obtain a colored (or altered) wood substrate, where a mineral
compound
that imparts the color or other desirable characteristic(s) to the wood
substrate is
formed in the colored or altered wood substrate. The mineral compound formed
comprises the products of a chemical reaction which occurs between the wood
substrate, a metal salt, and an oxygen source.
[0053] In the following description, components of the present water-based
wood
treatment solutions or kits, and/or steps of the process(es) described herein
could
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be modified, simplified, altered, omitted and/or interchanged, without
departing from
the scope of the present disclosure, depending on the particular applications
and the
desired end results which the water-based wood treatment solutions or kits are
intended for, as briefly exemplified herein and as also apparent to a person
skilled
in the art.
[0054] Furthermore, to provide a more concise description, some of the
quantitative
and qualitative expressions given herein may be qualified with the terms
"about" and
"substantially". It is understood that whether the terms "about" and
"substantially"
are used explicitly or not, every quantity or qualification given herein is
meant to refer
to an actual given value or qualification, and it is also meant to refer to
the
approximation to such given value or qualification that would reasonably be
inferred
based on the ordinary skill in the art, including approximations due to the
experimental and/or measurement conditions for such given value.
[0055] Also, the following terms have the following designated definitions,
unless
the context clearly indicates otherwise. All percentages referred to will be
expressed
in weight percent (%), based on total weight of the water-based wood treatment
solution(s), water-based tannin-rich treatment solution, or components
involved,
unless specified otherwise. The following abbreviations are used herein:
g=grams,
L=liters. Unless otherwise specified, ranges listed are to be read as
inclusive and
combinable and temperatures are in degrees Celsius ( C.).
[0056] Additionally, as used herein, "wood," "wood material" and/or "wood
substrate"
shall mean all forms of wood, for example, solid wood (such as timber or
lumber in
the form of logs, beams, planks, sheets, boards, etc.), wood composite
materials
(such as wood fiber board, chip board, particle board, etc.) and all products
made
from wood and wood-composite materials.
[0057] It is also noted that, in describing embodiments, specific terminology
is
employed for the sake of clarity. However, the description is not intended to
be
limited to the specific terminology so selected, and it is to be understood
that each
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specific element or component includes all technical equivalents which operate
in a
similar manner to accomplish a similar purpose. For the sake of simplicity,
this
description principally addresses application to wood substrates.
[0058] The present disclosure describes processes, water-based wood treatment
solutions, water-based tannin-rich treatment solutions and kits for treating
wood
substrates which, by virtue of their compositions, components and/or steps,
overcome or at least minimize some of the above-discussed drawbacks.
[0059] As it will be described in more details below, a water-soluble metal
(II) salt
and a water-soluble acetate salt dissolved in an aqueous solvent can be
incorporated into, or applied to, the wood substrate by treatment methods that
contact the wood substrate with the water-based wood treatment solution
obtained.
The treatment also involves a water-soluble tannin-rich material that is
dissolved in
the aqueous solvent together with the water-soluble metal (II) salt and the
water-
soluble acetate salt or, alternatively, a separate water-based tannin-rich
treatment
solution that includes the water-soluble tannin-rich material dissolved in a
distinct
aqueous solvent, as described in more details below. The water-based tannin-
rich
treatment solution can be used as a pre-treatment or post-treatment to the
water-
based wood treatment solution by being incorporated into, or applied to, the
wood
substrate by similar treatment methods.
Process for treating a wood substrate
Metal (II) salt and acetate salt
[0060] According to a non-limitative embodiment, a process for treating a wood
substrate which involves a water-based wood treatment solution is disclosed.
The
process includes a step of dissolving a water-soluble metal (II) salt and a
water-
soluble acetate salt in an aqueous solvent to obtain a water-based wood
treatment
solution with concentrations of the water-soluble metal (II) salt and the
water-soluble
acetate salt high enough to color the wood substrate. The aqueous solvent can
be
provided in a sufficient amount to completely (or almost completely) dissolve
the
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water-soluble metal (II) salt and the water-soluble acetate salt, and to
maintain them
in solution. A sufficient amount of the water-based wood treatment solution
obtained
can thus be contacted with the wood substrate so that the wood substrate can
be
colored (e.g., to obtain a brownish, blackish or grayish wood substrate).
Indeed, the
water-based wood treatment solution needs to be applied to the wood substrate
in
a sufficient amount so that at least a portion of the wood fibers present in
the wood
substrate are contacted with the water-based wood treatment solution. For
example,
the wood fibers present at the surface of the wood substrate can be
impregnated or
saturated with the water-based wood treatment solution. The coloration is
obtained
by allowing the water-soluble metal (II) salt, the water-soluble acetate salt
and the
wood substrate to chemically react so as to fix or bond the reaction products
to or
within the wood substrate.
[0061] In some implementations, the water-soluble metal (II) salt can include,
without limitation, iron salts (ferrous or ferric), such as iron chloride
salts, iron
bromide salts, iron fluoride salts, iron iodide salts, iron nitrate salts,
iron borate salts,
iron phosphate salts, iron pyrophosphate salts, iron carbonate salts, iron
sulfate
salts, iron titanate salts, chromates, silicates, halides, perchlorates,
permanganates,
thiosulfates, and the like. Oxides that are subject to reduction to release a
metal ion
capable of reacting with the oxygen source in the presence of the wood
substrate to
produce a color can also be used, so long as the metal ion or compound is
sufficiently
soluble to penetrate the wood substrate and is able to react with the oxygen
source
present in the water-based wood treatment solution to produce the desired
mineral
compound (i.e., the color). Other suitable water-soluble iron salts can
include,
without limitation, organic acid salts, such as acetate, formate, propionate,
stearate,
benzoate, citrate, D-gluconate, lactate and tartrate. The iron salt can
include "mixed"
salts of any of the aforementioned anionic counterions. In some
implementations,
the iron salt can be selected from one or more of chloride, bromide, nitrate
and
sulfate salts. In some implementations, the water-soluble wood treatment
solution
can include a combination of a plurality of water-soluble metal (II) salts.
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[0062] In some implementations, another metal salt can be involved. For
example,
the metal salt can be, without limitation, a salt of silver, cerium, copper,
magnesium,
molybdenum, nickel, tin, chromium, any combination, and the like, or a salt
of,
without limitation, antimony, beryllium, bismuth, cadmium, cobalt, gold,
iridium, lead,
manganese, mercury, niobium, osmium, platinum, plutonium, potassium, rhodium,
selenium, silicon, sodium, tantalum, thorium, tungsten, uranium, vanadium, any
combination and the like, as long as the metal salt can impart a desirable
color to
the wood substrate, once it has chemically reacted with both the wood
components
and the oxygen source.
[0063] Additional suitable water-soluble iron salts can include salts formed
by
interaction with organic compounds, such as complexed or chelated iron salts.
Suitable organic ligands that form complexes or chelates with ferric or
ferrous ions
include, for example, aromatic amines (such as 2,2'-bipyridine or 2,2'-
dipyridyl, 1 ,1 0-
phenanthroline and naphthyridine), polyamines (such as ethylenediamine and
diethylenetriamine) and anionic nucleophilic compounds (such as
acetylacetonate,
oxalate, catecholate, thiophenoxide, cyanide (CN-), nitrilotriacetic acid and
salts
thereof, and ethylenediaminetetraacetic acid and salts thereof).
[0064] In a non-limitative embodiment, the water-soluble metal (II) salt can
be,
without limitation, iron (II) chloride, iron (II) perchlorate, iron (II)
sulfate, copper (II)
chloride, copper (II) perchlorate, tin (II) sulfate, manganese (II) chloride,
titanium (II)
sulfate, any combination, and the like. More particularly, the water-soluble
metal (II)
salt can be, without limitation, iron sulfate (FeSO4) such as iron sulphate
heptahydrate (FeSO4 0 7 H20), iron sulphate monohydrate (FeSO4 0 H20),
ethylenediammonium sulfate ((CH2NH3)2 S040 FeSO4 0 4 H20), and the like.
[0065] In some implementations, the concentration of the water-soluble metal
(II)
salt in the water-based wood treatment solution can be between about 1 g/L and
about 10 g/L (w/v) between about 1.5 g/L and about 7 g/L, or between about 2
g/L
and about 5 g/L. More particularly, the concentration of the water-soluble
metal (II)
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salt in the water-based wood treatment solution can be between about 2 g/L and
about 3 g/L.
[0066] In some implementations, the water-soluble acetate salt can be any
water-
soluble acetate salt capable of penetrating the wood substrate and reacting
with the
water-soluble metal (II) salt to impart a stable color to the wood substrate.
In some
implementations, the water-soluble wood treatment solution can include a
combination of a plurality of water-soluble acetate salts.
[0067] In a non-limitative embodiment, the water-soluble acetate salt can be,
without
limitation, sodium acetate (C2H3Na02), such as sodium acetate trihydrate
(CH3COONa 3 H20), calcium diacetate x - hydrate ((CH3C00)2Ca x H20), and
the like.
[0068] In some implementations, the concentration of the water-soluble acetate
salt
in the water-based wood treatment solution can be between about 1 g/L and
about
g/L (w/v), between about 1.5 g/L and about 7 g/L, or between about 2 g/L and
about 5 g/L. More particularly, the concentration of the water-soluble acetate
salt in
the water-based wood treatment solution can be between about 2 g/L and about 3
g/L. It is noted that the concentrations of the water-soluble metal (II) salt
and of the
water-soluble acetate salt present in the water-based wood treatment solution
can
depend on a variety of factors, including, without limitation, the species,
size, type,
form and other characteristics of the wood substrate or wood product to be
treated
as well as the intended end use of the treated or colored wood substrate.
[0069] In a non-limitative embodiment, the water-based wood treatment solution
is
an aqueous solution comprising between about 2 g/L and 10 g/L (w/v) of the
water-
soluble metal (II) salt and between about 1 g/L and 10 g/L (w/v) of the water-
soluble
acetate salt.
[0070] In some implementations, a different oxygen source can be involved.
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Acid
[0071] In accordance with a non-limitative embodiment, the process can further
include dissolving a water-soluble acid in the aqueous solvent, together with
the
water-soluble metal (II) salt and the water-soluble acetate salt, prior to
contacting the
wood substrate with the water-based wood treatment solution. In one
implementation, the nature and concentration of the water-soluble acid added
in the
aqueous solvent can be such as to provide the water-based wood treatment
solution
with a pH of between about 4 and about 7, of between about 5 and about 6, or
of
between about 4 and about 5. A more acidic water-based wood treatment solution
can give a lighter and less uniform gray color, while a more basic water-based
wood
treatment solution can increase the amount of precipitate and can reduce the
coloring effect on the wood substrate. The water-soluble acid can act as a pH
regulator. It can keep the oxidation state at +2, which allows the
organometallic
complex to be completely dissolved, as it slows down the oxidation of the
metal (II)
salt. It also prevents the formation of precipitates.
[0072] In some implementations, the water-soluble acid can be an acid in solid
form.
In a non-limitative embodiment, the water-soluble acid can be sulfuric acid
(H2SO4),
acetic acid (CH3COOH), citric acid (C6H807), and more particularly, anhydrous
citric
acid.
[0073] For example, the concentrations of the water-soluble acid, the water-
soluble
metal (II) salt and the water-soluble acetate salt can be so as to obtain a
molar ratio
of acid : metal : acetate of between about 1: 3: 6 and about 1: 3: 30.
Tannin-rich material
[0074] As it will be described in more details below, the coloring of the wood
substrate is predominantly a result of the chemical reaction between the water-
soluble metal (II) salt and the wood phenolic compounds, such as tannins,
present
in the wood substrate. The content of tannins present in the wood substrate
can thus
affect the resultant color change. Therefore, the process further includes
dissolving
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a water-soluble tannin-rich material in the aqueous solvent, together with the
water-
soluble metal (II) salt and the water-soluble acetate salt, and optionally,
the water-
soluble acid, prior to contacting the wood substrate with the water-based wood
treatment solution. Wood substrates with low or no content of tannins can
therefore
be colored efficiently. In some implementations, the water-soluble tannin-rich
material can have a tannin content higher than about 40%, higher than about
50%,
higher than about 60%, higher than about 70%, higher than about 80%, or higher
than about 90%.
[0075] In some implementations, the water-soluble tannin-rich material can
include
epigallocatechin gallate, catechol, gallotannin and the like. In a non-
limitative
embodiment, the water-soluble tannin-rich material can include a logwood tree
extract, a mimosa tree extract, an oak gall extract, and the like. In a non-
limitative
embodiment, the water-soluble tannin-rich material can further include a tea
extract,
such as a black tea extract and a green tea extract, a wine extract, a coffee
extract,
and the like.
[0076] In some implementations, the concentration of the water-soluble tannin-
rich
material can be between about 2 g/L and about 100 g/L, or between about 2 g/L
and
about 50 g/L in the water-based wood treatment solution.
[0077] Instead of being dissolved in the aqueous solvent with the water-
soluble
metal (II) salt and the water-soluble acetate salt, it is noted that the water-
soluble
tannin-rich material can be dissolved in a separate aqueous solvent so as to
obtain
a separate water-based tannin-rich treatment solution which can be contacted
with
the wood substrate before or after contacting the wood substrate with the
water-
based wood treatment solution, as a pre-treatment or post-treatment. In
accordance
with a non-limitative embodiment, the process for treating the wood substrate
can
involve the water-based tannin-rich treatment solution, acting as a pre-
treatment
solution, as well as a water-based wood treatment solution to be applied in a
subsequent stage of the treatment. According to this scenario, the process can
include a step of dissolving a water-soluble metal (II) salt and a water-
soluble acetate
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salt, and optionally a water-soluble acid, in a first aqueous solvent to
obtain a water-
based wood treatment solution with concentrations of the water-soluble metal
(II)
salt and the water-soluble acetate salt high enough to color the wood
substrate. The
process can further include a step of dissolving a water-soluble tannin-rich
material
in a second aqueous solvent to obtain a water-based tannin-rich treatment
solution
with a concentration of the water-soluble tannin-rich material high enough to
at least
partially saturate the wood substrate. The process can thus include a step of
contacting the wood substrate with sufficient amounts of the water-based
tannin-rich
treatment solution and of the water-based wood treatment solution obtained. In
one
scenario, the concentration of the water-soluble tannin-rich material can be
between
about 2 g/L and about 25 g/L, or between about 2 g/L and about 5 g/L in the
water-
based tannin-rich solution.
[0078] To obtain the water-based wood treatment solution, measured amounts of
the water-soluble metal (II) salt and the water-soluble acetate salt are mixed
or
dissolved in a volume of the first aqueous solvent (e.g., in a volume of
water). To
obtain the water-based tannin-rich treatment solution, a measured amount of
the
water-soluble tannin-rich material is mixed or dissolved in a volume of the
second
aqueous solvent (e.g., in a volume of water). Alternatively, a measured amount
of
the water-soluble acid can be dissolved together with the water-soluble metal
(II) salt
and the water-soluble acetate salt into the first aqueous solvent.
[0079] As mentioned above, in some implementations, the wood substrate can be
contacted first with the water-based tannin-rich treatment solution, as a pre-
treatment step, to at least partially saturate the wood substrate and obtain a
pretreated wood substrate, and then, the pretreated wood substrate can be
contacted with the water-based wood treatment solution to color the wood
substrate
so as to obtain the colored wood substrate. By applying the water-based tannin-
rich
treatment solution first on the wood substrate, the tannin content of the wood
substrate can increase and the reaction between the wood substrate, the water-
soluble metal (II) salt and the water-soluble acetate salt can be favored to
form the
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mineral compound on, or within, the wood substrate, once the water-based wood
treatment solution has been applied thereon. It is further noted that
different colors,
darker colors for example, can be obtained by contacting the obtained colored
wood
substrate a second time with the water-based tannin-rich treatment solution,
as a
post-treatment step.
[0080] The water-based tannin-rich treatment solution can be applied to the
wood
substrate in a sufficient amount to at least partially saturate the wood
substrate, while
the water-based wood treatment solution can be applied to the wood substrate
or
the pre-treated wood substrate in a sufficient amount to react with the wood
substrate and/or the water-soluble tannin-rich material applied to the wood
substrate
so as to color the wood substrate. For example, the wood substrate can be
contacted
with the water-based tannin-rich treatment solution and the water-based wood
treatment solution for contact time periods sufficient so that at least a
portion of the
wood fibers present in the wood substrate are contacted with the water-based
tannin-rich treatment solution and the water-based wood treatment solution.
For
example, the wood fibers present at the surface of the wood substrate can be
impregnated and saturated with the water-based tannin-rich treatment solution
and
the water-based wood treatment solution, respectively.
[0081] Conversely, in some implementations, the wood substrate can be
contacted
with the water-based wood treatment solution (i.e., with the water-soluble
metal (II)
salt and the water-soluble acetate salt) first, to obtain a pretreated wood
substrate,
and then the pretreated wood substrate can be contacted with the water-based
tannin-rich treatment solution containing the water-soluble tannin material,
as a post-
treatment step, so as to obtain the desired colored wood substrate. Therefore,
the
order in which these water-based tannin-rich treatment and water-based wood
treatment solutions are applied on the wood substrate can lead to different
coloring
effects.
[0082] In other scenarios, the wood substrate can be contacted according to
different treatment stages with a first solution which contains the water-
soluble
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tannin-rich material, with a second solution which contains the water-soluble
metal
(II) salt and, with a third solution which contains the water-soluble acetate
salt (or
directly with the water-soluble acetate salt), as long as the chemical
interaction can
occur between the wood substrate (and the recently applied tannins or water-
soluble
tannin-rich material), the water-soluble metal (II) salt and the water-soluble
acetate
salt, and can allow the water-soluble metal (II) salt and the water-soluble
acetate salt
to form the mineral compound on, and/or within, the wood substrate.
[0083] It is further noted that different wood substrates, different water-
soluble metal
(II) salts, different water-soluble acetate salts, different water-soluble
acids and
different water-soluble tannin-rich materials can be involved in providing the
wood
substrate with different coloring effects.
Aqueous solvent
[0084] In one implementation, the aqueous solvent(s) can be water. It is noted
that
the water-based wood treatment solution and the water-based tannin-rich
treatment
solution can involve other solvent than substantially liquid aqueous solvent.
For
example, a water-based gel, a water-based paste, a water-based emulsion, or
other
thick water-based preparation can be used as the aqueous solvent(s), as long
as
such preparation is capable of delivering the water-soluble metal (II) salt,
the water-
soluble acetate salt (i.e., the oxygen source), and the water-soluble tannin-
rich
material, into or on the wood substrate so that the water-soluble metal (II)
salt, the
water-soluble acetate salt, the water-soluble tannin-rich material and the
wood
components can react to form the mineral compound (i.e., the grayish color).
Additives
[0085] It is also noted that the water-based wood treatment solution or the
water-
based tannin-rich treatment solution described above can further include a
compatible additive selected from the group consisting of, without limitation,
thickener, alcohol, emulsifier, additional coloring agent, additional pigment,
additional dye, bleach, sealer, finishing agent, tint, acrylic finish, latex
finish,
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polyurethane, gelling agent, surfactant, buffer, base, additional color,
additional salt,
stabilizer, antimicrobial agent, antifungal agent, insecticide, insect
repellant,
ultraviolet protectant, fire retardant, and the like. Other suitable additives
can be
employed as long as they do not interfere with the chemical reaction that
occurs
between the wood components, the water-soluble metal (II) salt, the water-
soluble
tannin-rich material and/or the water-soluble acid.
Form of the components
[0086] In some implementations, the water-soluble metal (II) salt, the water-
soluble
acetate salt, the water-soluble tannin-rich material and/or the water-soluble
acid can
be provided in solid form (e.g., in a powder form, in tablets, etc.), while in
some other
implementations, the water-soluble metal (II) salt, the water-soluble acetate
salt, the
water-soluble tannin-rich material and/or the water-soluble acid can come in a
concentrated liquid solution and can be diluted with the aqueous solvent(s) to
form
the water-based wood treatment solution or, alternatively, the water-based
wood
treatment solution and the water-based tannin-rich treatment solution. The
water-
soluble metal (II) salt and the water-soluble acetate salt can be added
substantially
simultaneously (i.e., at the same time) in the aqueous solvent. Alternatively,
the
water-soluble metal (II) salt and the water-soluble acetate salt can be
introduced in
the aqueous solvent one after the other, and in any order. The water-soluble
metal
(II) salt, the water-soluble acetate salt, the water-soluble tannin-rich
material and/or
the water-soluble acid can further be provided in separate and fully diluted
liquid
containers, ready to be mixed together to then be applied on a wood substrate.
Indeed, it remains important that at least the water-soluble metal (II) salt
and the
water-soluble acetate salt remain in different compartments prior they are
mixed
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together, so the reaction not only occurs between these two species, but
together
with the tannins of the wood substrate, increasing the coloring results.
Contact between water-based wood treatment solution and wood substrate
[0087] Suitable methods for contacting the wood substrate with the water-based
wood treatment and tannin-rich solutions can include, without limitation,
immersion,
brushing, spraying, rolling, dipping, pressure treatments (e.g., pressure
impregnation), and the like. In some implementations, such methods can be used
for contacting the wood substrate with the water-based wood treatment and with
the
water-based tannin-rich treatment solution, before its use in wooden
structures and
products. However, already built-in wood (e.g. flooring, cladding, etc.) can
also be
contacted with the water-based wood treatment solution and the water-based
tannin-
rich treatment solution using such techniques.
Operating conditions
Temperature
[0088] The wood substrate can be contacted with the water-based wood treatment
solution and the water-based tannin-rich treatment solution at temperatures
ranging
from about 4 C to about 100 C. More particularly, the wood substrate can be
contacted with the water-based wood treatment solution and the water-based
tannin-
rich treatment solution at temperatures ranging from about 10 C to about 50 C.
In
one implementation, the wood substrate can be contacted with the water-based
wood treatment solution and the water-based tannin-rich treatment solution at
room
temperature. In some implementations, the water-based wood treatment solution
and the water-based tannin-rich treatment solution can be applied to the wood
substrate at a temperature which is found to be between the freezing point and
the
boiling point of the obtained water-based wood treatment solution and the
water-
based tannin-rich treatment solution. In order to help dissolve the components
in the
aqueous solvent, the aqueous solvent can optionally be heated prior
introduction of
the components therein. For example, the aqueous solvents can be heated to a
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temperature of between about 40 C and about 90 C, or between about 60 C and
80 C prior dissolving the water-soluble metal (II) salt, the water-soluble
acetate salt,
the water-soluble tannin-rich material and optionally, the water-soluble acid
therein.
[0089] Once applied on the wood substrate, the water-based wood treatment
solution and the water-based tannin-rich treatment solution can be allowed to
dry,
under room conditions for example. An air stream (which can be heated or not)
can
optionally be involved in drying the wood substrate with the water-based wood
treatment solution and the water-based tannin-rich treatment solution applied
thereon. In some implementations, the wood substrate can be contacted with the
water-based tannin-rich treatment solution in order to form a first layer of
the water-
based tannin-rich treatment solution, once it has dried on the wood surface.
Another
or other layer(s) can be formed on the wood substrate with the water-based
tannin-
rich treatment solution and/or water-based wood treatment solution.
Pressure
[0090] In one implementation, contacting the wood substrate with the water-
based
wood treatment solution and the water-based tannin-rich treatment solution can
be
performed at atmospheric pressure. Alternatively, use of vacuum-pressure or
other
techniques can further be used to reduce treatment time and increase the level
of
penetration of the water-based wood treatment solution and the water-based
tannin-
rich treatment solution into the wood substrate or wood products, thereby
increasing
the effectiveness of the wood treatment (i.e., of the coloring treatment).
Application period
[0091] In a non-limitative implementation, the water-based wood treatment
solution
obtained needs to be applied on the wood substrate in a predetermined period
of
time (i.e., before a predetermined amount of time), just after the water-
soluble metal
(II) salt and the water-soluble acetate salt have been dissolved in the
aqueous
solvent, so that the reaction does not only occur in the water-based wood
treatment
solution containing the metal (II) salt and the acetate salt, but also,
together with the
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wood components (e.g., the tannins) and/or the tannins of the water-based
tannin-
rich treatment solution.
[0092] In a non-limitative implementation, the water-based tannin-rich
treatment
solution obtained needs to be applied on the wood substrate in a predetermined
period of time (i.e., before a predetermined amount of time), just after the
water-
soluble tannin-rich material has been dissolved in the aqueous solvent. For
example,
the application of the water-based tannin-rich treatment solution can be
performed
on the wood substrate before 6 months, before 1 month, or before 4 weeks after
the
water-soluble tannin-rich material has been dissolved in the aqueous solvent.
Preventing contact of some components
[0093] In a non-limitative implementation, direct contact of the water-soluble
metal
(II) salt with the water-soluble acetate salt needs to be prevented prior to
dissolving
the water-soluble metal (II) salt and the water-soluble acetate salt in the
aqueous
solvent, so that no reaction occurs between these components prior to
dissolution of
these components and thus, prior to application of the water-based wood
treatment
solution on the wood substrate. In other words, at least the water-soluble
metal (II)
salt and the water-soluble acetate salt can be kept apart from each other
before
mixing them in the aqueous solvent, otherwise, these components can react or
melt
together, and produce a water-based wood treatment solution unable to provide
the
desired coloring or aging effect to the wood substrate.
Pre-treatment
[0094] So that the water-based wood treatment solution can efficiently
penetrate the
wood substrate (i.e., it can reach a maximum depth), prior to contacting the
wood
substrate with the water-based wood treatment solution and/or with the water-
based
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tannin-rich treatment solution, the wood substrate can be washed, sandblasted,
prepared, etc.
Post-treatment
[0095] In some implementations, the colored wood substrate obtained can
receive
a final surface treatment. For example, final or polishing solution(s) can be
applied
on the colored wood substrate. Indeed, oils, varnishes, waxes, paints, etc.
can be
applied on the colored wood substrate obtained.
Wood substrate
[0096] In some implementations, the wood substrate can be selected from wood
species such as, without limitation, white cedar, red cedar, white spruce,
fir, balsam
fir, white pine, red pine, aspen or trembling aspen, silver maple, larch,
walnut, white
birch, sweet cherrywood, red oak, white ash, black ash, ipe, brazilwood, sour
cherrywood, quaking aspen, and the like. In some implementations, the wood
substrate to be treated can have a moisture content of less than 20%. However,
in
some implementations, the wood substrate to be treated can have a moisture
content between about 20% and about 100%. Therefore, it is not required that
the
wood substrate be completely dried before treating it with the water-based
wood
treatment solution and/or with the water-based tannin-rich treatment solution.
Water-based wood treatment solution and water-based tannin-rich treatment
solution
[0097] In accordance with another non-limitative embodiment, a water-based
wood
treatment solution for treating a wood substrate is disclosed. The water-based
wood
treatment solution includes a water-soluble metal (II) salt, a water-soluble
acetate
salt, a water-soluble tannin-rich material and an aqueous solvent to obtain
the water-
based wood treatment solution with concentrations of the water-soluble metal
(II)
salt, the water-soluble acetate salt and the water-soluble tannin-rich
material high
enough to at least partially saturate and color the wood substrate, as
described
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above. Again, in some implementations, the water-based wood treatment solution
can further include a water-soluble acid.
[0098] In accordance with a further non-limitative embodiment, a water-based
wood
treatment solution and a water-based tannin-rich treatment solution for
treating a
wood substrate are disclosed. The water-based wood treatment solution includes
a
water-soluble metal (II) salt, a water-soluble acetate salt and a first
aqueous solvent
to obtain the water-based wood treatment solution with concentrations of the
water-
soluble metal (II) salt and the water-soluble acetate salt high enough to
color the
wood substrate, as described above. In some implementations, the water-based
wood treatment solution can further include a water-soluble acid. On the other
hand,
the water-based tannin-rich treatment solution includes a water-soluble tannin-
rich
material and a second aqueous solvent to obtain the water-based tannin-rich
treatment solution with concentration of the water-soluble tannin-rich
material high
enough to at least partially saturate the wood substrate, prior or after it
has been
contacted with the water-based wood treatment solution.
Kit for treating a wood substrate
[0099] In accordance with another non-limitative embodiment, there is provided
a
kit for treating a wood substrate. The kit comprises a pouch which comprises a
water-
soluble metal (II) salt in solid form, a pouch which comprises a water-soluble
acetate
salt in solid form, a pouch which comprises a water-soluble tannin-rich
material in
solid form and a user guide which provides instructions for dissolving a dose
of the
water-soluble metal (II) salt and a dose of the water-soluble acetate salt in
an amount
of an aqueous solvent to thereby obtain a water-based wood treatment solution
having a concentration of water-soluble metal (II) salt and water-soluble
acetate salt
sufficient to allow the water-based wood treatment solution to color the wood
substrate. The user guide further provides instructions for dissolving a dose
of the
water-soluble tannin-rich material in the aqueous solvent along with the water-
soluble metal (II) salt and the water-soluble acetate salt. The user guide
alternatively
provides instructions for dissolving a dose of the water-soluble tannin-rich
material
-24 -
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in another (in a second) aqueous solvent to thereby obtain a separate water-
based
tannin-rich treatment solution having a concentration of water-soluble tannin-
rich
material sufficient to allow the water-based tannin-rich treatment solution to
at least
partially saturate the wood substrate. The pouch can be a container envelop or
the
like and has a predetermined amount of a water-soluble metal (II) salt, a
water-
soluble acetate salt or a water-soluble tannin-rich material. The kit can
further include
a pouch which comprises a water-soluble acid in solid form, and the user guide
can
further provides instructions for dissolving a dose of the water-soluble acid
in the
aqueous solvent along with the water-soluble metal (II) salt and the water-
soluble
acetate salt so as to adjust the pH of the water-based wood treatment
solution. The
water-soluble acid can indeed slow down the chemical reaction and prevent the
water-based wood treatment solution from precipitating.
[00100]The water-soluble metal (II) salt and the water-soluble acetate salt
can be
dissolved substantially simultaneously, or subsequently, in the aqueous
solvent to
obtain the water-based wood treatment solution with concentrations of the
water-
soluble metal (II) salt and the water-soluble acetate salt high enough to
color the
wood substrate. At least the pouches containing the water-soluble metal (II)
salt and
the water-soluble acetate salt can be hermetic (i.e., airtight), so that the
water-
soluble metal (II) salt and the water-soluble acetate salt do not react with
air or
oxygen prior to being dissolved in their aqueous solvent.
Chemical reactions
[00101]As mentioned above, the water-soluble metal (II) salt can be iron
sulfate,
while the water-soluble acetate salt can be sodium acetate. The mixture of
iron
sulfate in the aqueous solvent is believed to create ferrous acetate. Ferrous
acetate
formed, which is soluble in water, is slowly oxidized by oxygen, present in
sodium
acetate salt, to ferric acetate. Ferrous acetate (or ferric acetate) is
believed to
accelerate the oxidation of components such as lignin and tannins, which are
present
in the wood substrate. These two components are composed, among other, of
numerous phenol groups. The purpose of the metal (II) salt is therefore to
accelerate
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the oxidation of the lignin and the tannins present in the wood substrate,
while the
main objective of the acetate salt is to favor penetration of the solution
into the wood.
[00102] Indeed, the water-soluble metal (II) salt and the water-soluble
acetate salt
are dissolved in the aqueous solvent and applied on the wood substrate to
penetrate
or impregnate it. They react together, and with the wood components, and the
water-
soluble tannin-rich material, to produce the mineral compound which will be
affix on
the external surface of the wood substrate, and/or within the wood substrate.
Impregnation of the water-soluble metal (II) salt and the water-soluble
acetate salt
into the wood substrate is therefore accomplished by use of the aqueous
solvent.
The combination of mutually compatible water-soluble metal (II) salt, water-
soluble
acetate salt, water-soluble tannin-rich material and wood substrate brings
about an
in situ reaction, and modifies the wood substrate to provide it with the
desired
coloring effect.
[00103]The mineral compound that is produced by contacting with the wood
substrate the water-based wood treatment solution containing the water-soluble
metal (II) salt, the water-soluble acetate salt and the water-soluble tannin-
rich
material (or alternatively by contacting with the wood substrate the water-
based
wood treatment solution containing the water-soluble metal (II) salt and the
water-
soluble acetate salt, and the water-based tannin-rich treatment solution
containing
the water-soluble tannin-rich material) is linked to the wood substrate, is
stable and
long-lasting or permanent, and is immobilized or insolubilized in the wood
substrate.
As mentioned above, a wide variety of water-soluble metal (II) salts, water-
soluble
acetate salt, water-soluble tannin-rich material and/or wood substrate can be
used
depending on the desired coloring effect. The process(es) defined thus allow a
water-soluble metal (II) salt and a water-soluble acetate salt to react with
the wood
substrate and the water-soluble tannin-rich material applied thereon to
provide a
stable color effect, while preserving the integrity of the wood substrate.
[00104] Upon application of the water-based wood treatment solution (or water-
based wood treatment solution and water-based tannin-rich treatment solution)
on
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the wood substrate, the chemical reaction occurs between the tannin phenols,
which
are present in the wood substrate, and optionally in the water-soluble tannin-
rich
material. Indeed, the tannin phenols allow chelation of the metal ions. The
water-
soluble metal (II) salt, depending on its concentration and the pH of the wood
substrate to be treated or colored, will change the color of the phenols
contained in
the wood substrate. The reaction is accelerated by the presence of oxygen
present
in the water-soluble acetate salt and the aqueous solvent. The treatment
process
therefore allows the color modification of the wood substrate using the
chemical
reaction between the wood phenolic compounds, such as tannins present in the
wood substrate, and the water-soluble metal (II) salt forming the water-based
wood
treatment solution.
[00105] Although the process is not intended to be limited to the mechanism of
action,
it is believed that the oxygen present in the water-soluble acetate salt
causes an
oxidation reaction, bonding the water-soluble metal (II) salt to or among the
cellulose
fibers present in the wood substrate, a process referred to here as
"crosslinking".
The chemical nature of the crosslinking reaction is suggested by the fact that
a color
change results from the combination of the water-soluble metal (II) salt and
the
water-soluble acetate salt both present in the water-based wood treatment
solution,
and the wood substrate. The resulting color, unlike the water-based wood
treatment
solution and its components, is not water-soluble.
[00106]The process therefore involves saturating the fibers of the wood
substrate
with the water-soluble metal (II) salt present in the water-based wood
treatment
solution in a water-soluble form and then, oxidizing the water-soluble metal
(II) salt
in the fibers of the wood substrate to change the color, texture, and/or
general
appearance of the wood substrate. The water-based wood treatment solution
containing the water-soluble metal (II) salt soaks into the wood substrate,
impregnating it with mineral ions, which are then converted by the oxygen
source
(i.e., the water-soluble acetate salt) into an insoluble coloring compound.
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[00107] By contacting the wood substrate with the water-based wood treatment
solution (or water-based wood treatment solution and water-based tannin-rich
treatment solution) defined above, the wood substrate gets a darker shade
(e.g., a
gray shade), while its natural texture and general integrity are preserved
(e.g., the
treatment does not affect the strength of the wood substrate bonded joints.),
so it
can aesthetically resemble the desired aged wood substrates.
[00108]As mentioned, the content of phenolic compounds such as tannins present
in the wood substrate and alternatively water-soluble tannin-rich material can
affect
the resultant color change. Therefore, upon contact of the wood substrate with
the
treatment solution (or pre-treatment and treatment solutions), wood substrates
with
high contents of phenolic compounds can darken considerably, while wood
substrates with low contents of phenolic compounds can darken slightly.
[00109]The processes, water-based wood treatment solution, water-based tannin-
rich treatment solution and kits described above can satisfy a need for a
water-
based, non-toxic wood treatment that provides a substantially permanent even
coloring or aging effect to the wood substrate.
[00110] While the prior art wood treatment processes present many drawbacks,
the
treatment processes described above allow to rapidly obtain coloring results,
while
emitting no other and preventing the treatment solutions to precipitate once
the
components (at least the water-soluble metal (II) salt and water-soluble
acetate salt)
have been introduced into the aqueous solvent. The mixture of the components
into
the aqueous solvent creates an oxidizing treatment for the wood substrate,
instantly,
which has known concentrations. An easy industrial scaling can therefore be
performed.
[00111]As mentioned above, almost instantly after the water-based wood
treatment
solution has been applied on the wood substrate, the wood substrate is altered
to
obtain a grayish color, which mimics the appearance of an aged wood substrate.
Depending on the species of the wood substrate to be treated, the color
obtained
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can vary from light gray to dark gray, or can be silver gray, as the oxidation
reaction
occurring between the wood substrate (and the water-soluble tannin-rich
material),
the water-soluble metal (II) salt and the water-soluble acetate salt will
depend on the
concentration of tannins, and on the degradation rate of the tannins present
on, or
within, the wood substrate. The present water-based wood treatment solution
and
water-based tannin-rich treatment solution thus allow the graying of young
wood
substrates to mimic the look of a weathered piece of barn wood, for example,
while
retaining the original quality of the wood, by accelerating the natural
oxidation of the
wood substrate. The color modification occurs substantially instantly, while
it can
take several weeks, months or years to obtain similar results under natural
oxidizing
conditions, UV rays and/or weather conditions.
[00112] The need for volatile organic solvents and toxic compounds is also
avoided.
Moreover, heating or pressurizing steps can be employed prior, during and/or
after
application of the solutions, but are not required to obtain the desired end
results.
The treatment process is thus simple enough to be used by an amateur.
[00113]The water-based wood treatment solution and the water-based tannin-rich
treatment solution described are completely water-based. The process does not
require a binder of any kind, petroleum products, organic solvents, acrylic
resins,
dyes, or other expensive or toxic materials. The component materials have low-
impact on both the environment and human health. The unique characteristics of
these treatment solutions, their permanence even in exterior applications,
their
ability to evenly stain extremely soft woods and penetrate extremely hard
woods,
their simulated aging of wood, and the richness of the colors achieved can
appeal
even to those completely unconcerned about its environmental and health
advantages.
[00114] It is noted that contacting the wood substrate with the water-based
wood
treatment solution, and alternatively, water-based tannin-rich treatment
solution,
can also impart other chemical or physical effects to the wood substrate.
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020171-0004
EXPERIMENTS AND RESULTS
[00115] Different combinations of water-soluble metal (II) salt, of water-
soluble
acetate salt, of water-soluble tannin-rich material and of water-soluble acid
were
tested to obtain suitable water-based wood treatment solutions and/or water-
based
tannin-rich solutions. Wood substrates were contacted with the obtained water-
based wood treatment solutions and/or water-based tannin-rich solutions and
coloring results were assessed.
Experiment no. 1
[00116]The water-based wood treatment solution was prepared according to the
following steps. 1 Liter of water was heated to about 60 C-80 C. 2.78 g of
iron
sulphate heptahydrate (FeSO4 0 7 H20, green powder) (34.4%), 2.72 g of sodium
acetate trihydrate (NaC2H302 0 3 H20, white crystals) (33.7%), 0.58 g of
anhydrous
citric acid (C6H807 anh.) (7.2%) and 2 g of logwood tree extract (hematoxylin)
(24.8%), all in the powder form, were dissolved in the heated water. It is
noted that
the sodium acetate trihydrate can be dissolved in water prior to dissolving
the iron
sulphate heptahydrate so as to facilitate its dissolution. The obtained water-
based
wood treatment solution turned black without precipitating. It was then
applied on a
White Birch wood using a paintbrush.
[00117]The water-based wood treatment solution was allowed to dry on the wood
for about 30-45 minutes. The wood was provided with a light gray color only
after
few minutes. It is noted that the powders remained separated before their
dissolution
into water. Also, it is noted that the obtained water-based wood treatment
solution
has a shelf life of about 1 week, if conserved in a hermetic, and non-metallic
environment.
Experiment no. 2
[00118]A water-based wood treatment solution was prepared according to the
following steps. 2.78 g of iron sulphate heptahydrate (FeS040 7 H20) (45.7%),
2.72
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Date Recue/Date Received 2020-12-16
020171-0004
g of sodium acetate trihydrate (NaC2H3020 3 H20) (44.7%) and 0.58 g of
anhydrous
citric acid (C6H807 anh.) (9.6%), all in the powder form, were dissolved in 1
L of
water. Another liter of water was heated to about 60-80 C, and a water-based
tannin-
rich treatment solution was obtained by dissolving 2 g of logwood tree extract
(hematoxylin) (100%) in the heated water. The obtained water-based wood
treatment solution containing iron sulfate, sodium acetate and citric acid
turned pale
yellow without precipitating, while the water-based tannin-rich treatment
solution
containing the logwood tree extract turned reddish brown. Over time and under
exposure to air, the yellowish water-based wood treatment solution oxidized
and
turned orange (without precipitating). The water-based tannin-rich treatment
solution
was applied on a white birch wood using a paintbrush. The water-based tannin-
rich
treatment solution was allowed to dry on the wood for about 30 minutes. Then,
the
water-based wood treatment solution was applied on the pretreated white birch
wood
with the paintbrush. The water-based wood treatment solution was allowed to
dry on
the wood for about 45 minutes. The wood was provided with a gray color only
after
few minutes. It is noted that the powders remained separated before their
dissolution
into water. Also, it is noted that the obtained water-based wood treatment
solution
has a shelf life of about 1 year, if conserved in a hermetic, and non-metallic
environment.
[00119] The color tone or finish varies with the chosen wood species that were
treated and the chosen treatment process (water-based tannin-rich treatment
solution applied as the pretreatment step or together with the water soluble
metal (II)
salt and the water-soluble acetate salts of the water-based wood treatment
solution).
[00120] Reactions (and resultant color and textural appearance of the wood
substrate) varies with the substrate material. In the experiments presented
above,
white birch was treated with the treatment solution(s). However, it is noted
that other
wood species were successfully treated with these treatment solutions (white
cedar,
red cedar, sweet cherrywood, red oak, spruce, silver maple, white ash, black
ash,
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Date Recue/Date Received 2020-12-16
020171-0004
ipe or brazilwood, larch, sour cherrywood, white pine, red pine, fir, quaking
aspen,
walnut, alder, mahogany and basswood).
[00121]As mentioned, the coloring results also varies with the number of
layers
applied on the wood surface (or with the treatment process: water-based tannin-
rich
treatment solution applied as the pretreatment step or water-soluble tannin-
rich
material applied together with the water-soluble metal (II) salt and the water-
soluble
acetate salts). In general, starting with one layer of the water-based tannin-
rich
treatment solution (the dissolved logwood tree extract) and finishing with one
or more
applications of the water-based wood treatment solution yields to darker
grayish
colorations.
[00122]The obtained treated wood substrates have been subjected to accelerated
weathering situations, exposure to sun, hot water, freezing temperatures,
harsh rain
conditions, etc. The wood substrates tested were found to be resistant to such
conditions. These tests show that the obtained treated wood substrate or
products
are permanently colored and suitable for use according to interior and
exterior
applications.
Other experimentations
[00123] White cedar (Thuya occidentalis): When contacting the wood substrate
with
a single water-based wood treatment solution containing iron salt, sodium
acetate,
citric acid and logwood tree extract, the color of the wood substrate changed
from
yellow to gray. When contacting the wood substrate with the water-based tannin-
rich
treatment solution containing the logwood tree extract and then, with the
water-
based wood treatment solution containing iron salt, sodium acetate and citric
acid,
the color of the wood substrate changed from yellow to gray.
[00124] Red cedar (Thuya plicate): When contacting the wood substrate with a
single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from reddish
to
reddish-gray. When contacting the wood substrate with the water-based tannin-
rich
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Date Recue/Date Received 2020-12-16
020171-0004
treatment solution containing the logwood tree extract and then, with the
water-
based wood treatment solution containing iron salt, sodium acetate and citric
acid,
the color of the wood substrate changed from reddish to gray.
[00125] White spruce (Picea glauca): When contacting the wood substrate with a
single water-based wood treatment solution containing iron salt, sodium
acetate,
citric acid and logwood tree extract, the color of the wood substrate changed
from
yellowish-white to pale gray or dark gray. When contacting the wood substrate
with
the water-based tannin-rich treatment solution containing the logwood tree
extract
and then, with the water-based wood treatment solution containing iron salt,
sodium
acetate and citric acid, the color of the wood substrate changed from
yellowish-white
to a pale gray or dark gray of uniform tone.
[00126] Fir (Abies balsamea): When contacting the wood substrate with a single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from
yellowish-
white to pale gray or dark gray. When contacting the wood substrate with the
water-
based tannin-rich treatment solution containing the logwood tree extract and
then,
with the water-based wood treatment solution containing iron salt, sodium
acetate
and citric acid, the color of the wood substrate changed from yellowish-white
to a
pale gray or dark gray of uniform tone.
[00127] White Pine (Pinus Strobus): When contacting the wood substrate with a
single water-based wood treatment solution containing iron salt, sodium
acetate,
citric acid and logwood tree extract, the color of the wood substrate changed
from
yellow to gray or brownish gray. The variability depended on the original tone
of the
wood. When contacting the wood substrate with the water-based tannin-rich
solution
containing the logwood tree extract and then, with the water-based wood
treatment
solution containing iron salt, sodium acetate and citric acid, the color of
the wood
substrate changed from yellow to a uniformly distributed gray color.
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Date Recue/Date Received 2020-12-16
020171-0004
[00128]Aspen or trembling aspen (Populus tremuloides): White Pine (Pinus
Strobus): When contacting the wood substrate with a single water-based wood
treatment solution containing iron salt, sodium acetate, citric acid and
logwood tree
extract, the color of the wood substrate changed from yellowish-white to pale
gray.
When contacting the wood substrate with the water-based tannin-rich treatment
solution containing the logwood tree extract and then, with the water-based
wood
treatment solution containing iron salt, sodium acetate and citric acid, the
color of
the wood substrate changed from yellowish-white to a uniform distribution of a
deeper tone of gray.
[00129] Silver maple (Acer saccharinum): When contacting the wood substrate
with
a single water-based wood treatment solution containing iron salt, sodium
acetate,
citric acid and logwood tree extract, the color of the wood substrate changed
from
yellow to silvery gray. When contacting the wood substrate with the water-
based
tannin-rich treatment solution containing the logwood tree extract and then,
with the
water-based wood treatment solution containing iron salt, sodium acetate and
citric
acid, the color of the wood substrate changed from yellow to a deep silvery
gray.
[00130] Larch (Larix laricina): When contacting the wood substrate with a
single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from light
brown
to dark gray. When contacting the wood substrate with the water-based tannin-
rich
treatment solution containing the logwood tree extract and then, with the
water-
based wood treatment solution containing iron salt, sodium acetate and citric
acid,
the color of the wood substrate changed from light brown to dark gray.
[00131] Cherry (Prunus avium): When contacting the wood substrate with a
single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from reddish
to
dark gray or from yellowish to pale gray or silvery gray. When contacting the
wood
substrate with the water-based tannin-rich treatment solution containing the
logwood
tree extract and then, with the water-based wood treatment solution containing
iron
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Date Recue/Date Received 2020-12-16
020171-0004
salt, sodium acetate and citric acid, the color of the wood substrate changed
from
reddish to a deeper tone of dark gray or from yellowish to a deeper tone of
silvery
gray.
[00132] Walnut (Junglans regia): When contacting the wood substrate with a
single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from dark
brown
to black or from pale brown to gray. When contacting the wood substrate with
the
water-based tannin-rich treatment solution containing the logwood tree extract
and
then, with the water-based wood treatment solution containing iron salt,
sodium
acetate and citric acid, the color of the wood substrate changed from reddish
to a
deeper tone of dark gray or from dark brown to black or from pale brown to
gray.
[00133] Red alder (Alnus rubra): When contacting the wood substrate with a
single
water-based wood treatment solution containing iron salt, sodium acetate,
citric acid
and logwood tree extract, the color of the wood substrate changed from a rust
red to
gray. When contacting the wood substrate with the water-based tannin-rich
treatment solution containing the logwood tree extract and then, with the
water-
based wood treatment solution containing iron salt, sodium acetate and citric
acid,
the color of the wood substrate changed from reddish to a deeper tone of dark
gray.
[00134]African mahogany (Khaya ivorensis): When contacting the wood substrate
with a single water-based wood treatment solution containing iron salt, sodium
acetate, and citric acid, the color of the wood changed from a pink to a dark
grey.
When contacting the wood substrate with the water-based tannin-rich treatment
solution containing the logwood tree extract and then, with the water-based
wood
treatment solution containing iron salt, sodium acetate and citric acid, the
color of
the wood substrate changed from a pink to a dark grey.
[00135] American basswood (Tilia Americana): When contacting the wood
substrate
with a single water-based wood treatment solution containing iron salt, sodium
acetate, and citric acid, the color of the wood changed from a light beige
yellow to a
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Date Recue/Date Received 2020-12-16
020171-0004
light grey. When contacting the wood substrate with the water-based tannin-
rich
treatment solution containing the logwood tree extract and then, with the
water-
based wood treatment solution containing iron salt, sodium acetate and citric
acid,
the color of the wood substrate changed from a light beige yellow to a deeper
tone
of silvery grey.
[00136]Although the present invention has been described hereinabove by way of
specific embodiments thereof, it can be modified without departing from the
spirit
and nature of the subject invention defined in the appended claims.
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Date Recue/Date Received 2020-12-16
